The field of endoscopy, to which the present invention relates, includes medical diagnostic and therapeutic disciplines that utilize endoscopes to view otherwise inaccessible body cavities using minimally invasive surgical procedures. Endoscopic cameras are typically small and lightweight for ease of use by medical professionals. Typically, the camera is connected to a Camera Control Unit (“CCU”), with the CCU processing and displaying image data from the camera. Often, each medical procedure requires a different camera having different imaging capabilities, leading to a large inventory of cameras. Additionally, each camera must be compatible with the CCU to function correctly.
In known systems, cameras, such as charge coupled devices and the like, used during endoscopic surgery are typically referred to as heads or camera heads. To achieve the desired size and weight of the camera heads, camera head and/or integrated endoscope-camera assembly electronics are typically separated physically from the majority of circuitry required to process and output high-quality, color video images, which is typically housed in the CCU. In known systems, CCUs may be placed on or in carts, or may be permanently wall-mounted.
When image data is acquired, or picked up, it is sent by the camera head to the CCU. Upon receiving the image data from the camera head, the CCU normally processes the signal to display the acquired image on a viewing device. Generally, the image is used by a medical professional and/or for storage on various media (video cassette recorder, floppy disk, hard drives, flash drives, compact disks, digital video disks, and the like) and/or for transmission to remote locations in various manners, such as by the Intranet, Internet, radio transmission, and the like.
Additionally, the CCU may send commands to the camera head to adjust various settings, such as electronic shutter for light sensitivity, and other optical and electronic characteristics.
It is known to provide a CCU that, at any one time, is capable of supporting one of a limited number of compatible camera heads, where each camera head may have different settings and a distinct image signal format. For example, each camera head may have its own unique white balance calibration requirements and settings. White balance includes the process of removing unrealistic color casts, performing color correction, and establishing color fidelity so that objects which appear white in person are rendered white in the image or video. In the medical field, maintaining color fidelity in the camera head and CCU is important because medical professionals routinely make diagnostic decisions based on the appearance, i.e. color, of anatomical structures. Therefore, if a camera's white balance is not properly set, the resulting diagnosis made by the medical professional using the camera may be incorrect and cause adverse, and at times catastrophic, consequences for the patient.
For a conventional CCU having a single camera head coupled thereto, “white balancing” the head is performed prior to the start of a medical procedure. This process requires that the medical professional hold the camera head, aim the camera's objective lens and corresponding light source towards a white surface (e.g., white gauze, white balance card) such that the camera's field of view is filled by the white surface, and engage a control button on the CCU or on the camera head to start white balancing the camera head.
However, conventional CCUs suffer from several disadvantages with respect to their white balance capability. For example, conventional CCUs fail to provide efficient and secure means for white balancing multiple camera heads that are coupled to the control unit. Moreover, the CCUs fail to provide efficient and reliable means for white balancing a select group of camera heads from among a plurality of camera heads coupled to the control unit. Some CCUs which have a limited number of camera heads are configured with multiple white balance calibration buttons, each button being designated to calibrate a specific camera head. However, with such a setup, there is often no easy or readily apparent way to tell which calibration button is linked to which camera. Accordingly, a medical professional may accidentally and unknowingly calibrate the wrong camera and use an uncalibrated camera during a medical procedure. In order to avoid making this mistake, the medical professional would have to take time to trace the transmission cable connecting a selected camera back to the CCU from among multiple transmission cables connecting other cameras to the CCU. This tedious task may further be complicated if the transmission cables are coupled to the CCU via a rear connection panel that is not easily accessible.
A conventional CCU is also unable to efficiently and properly determine from a group of active camera heads a specific camera to white balance. With multiple image signals being transmitted from the active camera heads, the CCU is unable to reconcile which camera head (i.e., the camera which the medical professional plans to use) must be calibrated for white balance. Instead of trying to trace a particular camera head back to the CCU to determine the correct white balance calibration button to engage, the medical professional may calibrate all the camera heads coupled to the CCU in order to prevent the potential for misdiagnosis due to use of an uncalibrated camera head. However, calibrating all cameras coupled to the CCU takes additional time that is unnecessary when the medical professional requires use of only one specific camera for a given medical procedure.
Other conventional CCUs may not incorporate or have an integrated white balance functionality. As an alternative, each camera head attached to the CCU is equipped with its own calibration button. However, this particular CCU-camera configuration has its own disadvantages. The CCUs often lack the capacity to deactivate the white balance calibration buttons on the camera heads. As such, there is the possibility that the medical professional may accidentally engage the calibration button while the camera head is in use, i.e., inserted within a patient. Calibrating the camera head while it is disposed within a body cavity will establish a distorted color balance setting and provide defective color fidelity in the image signal. The medical professional would have to cease the surgical operation, remove the endoscope-camera from the patient, repeat white balance calibration of the camera (pointing the camera at a white surface to form a baseline for calibration), carefully reinsert the endoscope to its previous position within the incision and cavity made within the patient, and thereafter continue with the surgical operation. Accordingly, the medical professional must stop the surgical operation for a significant downtime to correct the accidental calibration of the camera head.
Another disadvantage which conventional CCUs have is their inability to provide dual white balance for multiple camera heads coupled to the CCU, wherein the camera heads have multi-spectral imaging capability (i.e., wide band imaging and narrow band imaging) and/or comprises different light source technology. More specifically, prior art CCUs often do not provide color correction for multiple camera heads having different light sources, such as white light cystoscopic cameras and blue light photodynamic diagnostic (PDD) cystoscopic cameras. An extended color balance range is required in order to correctly calibrate PDD cameras for color fidelity compared to typical white light cameras. Conventional CCUs are unable to detect or distinguish the different cameras and often lack the technology and capability to perform dual white balance (white balance for both white light and blue imaging technology).
Further, conventional CCUs do not have the capability to perform dual white balance on a plurality of active camera heads such that the images from different camera heads have matching picture quality and characteristics (e.g., color balance, hue, saturation, contrast, brightness).
It is further noted that conventional CCUs often lack the capability to function with multiple cameras/video endoscopes having diverse types of imaging technology (e.g., CCD sensors, analog CMOS sensors, digital CMOS sensors) and distinct white balance calibration requirements. Often, such cameras do not work well together when connected to a common CCU. Typically, conventional CCUs are designed so that they are compatible only with a particular family of camera heads having the same imaging design and white balance calibration requirements.
In light of several disadvantages of conventional CCUs, it is therefore desired to overcome these disadvantages and provide an imaging system that can function with a plurality of camera heads, efficiently calibrate the white balance of all active camera heads, and protect their white balance settings from unintentional adjustments. It is also desired to provide a CCU that can perform dual white balance calibration on one or more multi-spectral imaging camera heads coupled thereto. Further, it is desired to provide a CCU that is capable of calibrating the white balance of more than one active camera such that a common image quality may be achieved among the cameras.